Conventional flow-through centrifuges utilize rotating seals which can become a source of leaks between the inflow and the outflow lines. The rotating seals represent a weak point in the machinery in terms of the performance life time, complexity and fragility of its parts and the necessity for a continuous and comparable degree of lubrication, all shortcomings of prior art centrifuges of flow-through type. These shortcomings are distinct disadvantages no matter what materials are to be centrifuged on a flow-through basis.
When these continuous-flow centrifuges are adapted for an on-line blood separation, as applied to the collection of blood cells, rotating seals become critical in terms of platelet injury, red cell hemolysis, and obstruction of the channels by aggregates and impaired lubrication of the rotating seals.